Field of the Invention
The present invention relates to production of a multiband image made of spectral images of four or more different wavelength bands.
Description of the Related Art
A multiband image is effective in identifying the kind of an imaged object and in examining the state of the object, and is exploited in various fields such as remote sensing, biotechnology, medical science, and machine vision. The multiband image is also exploited in the field of computer graphics so as to precisely depict colors of the object. The multiband image has a three-dimensional structure of two spatial dimensions and one wavelength dimension. Different methods for acquiring the multiband image yield different spatial resolutions, wavelength resolutions, and temporal resolutions for the image.
U.S. Patent Application Publication No. 2010/0140461 discloses a method of acquiring a multiband image through an array of color filters that are disposed on an image sensor and have spectral transmittances different from each other. U.S. Patent Application Publication No. 2007/0296965 discloses a method of acquiring a multiband image through combination of image estimation processing and a compression sensing optical system including an encoding mask and a dispersive element. These methods disclosed in U.S. Patent Application Publication No. 2010/0140461 and U.S. Patent Application Publication No. 2007/0296965 can acquire a multiband image with single image capturing and thus yield a high temporal resolution.
J. M. Bioucas-Dias and M. A. T. Figueiredo, “A new TwIST: two-step iterative shrinkage/thresholding algorithms for image restoration”, IEEE Trans. on Image Processing, vol. 16, Dec. 2007 discloses a fast image estimation processing algorithm such as TwIST (Two-Step Iterative Shrinkage/Thresholding) algorithm.
In the method disclosed in U.S. Patent Application Publication No. 2010/0140461, light incident on a pixel has a single wavelength band. Thus, an increase in the wavelength resolution results in a decreased incident light amount and a decreased image capturing sensitivity. The method disclosed in U.S. Patent Application Publication No. 2007/0296965 requires a multi-imaging optical system and thus an increased size of the system.